Increased monoester lipase activity of red blood cells in alcoholism

Monoester lipase activity was assayed by a radiochemical assay in the red blood cells (RBC) from 50 chronic alcoholic patients within 48 hr after discontinuation of chronic alcohol intake and from 40 nonalcoholic control subjects. The mean value of lipase activity was increased to 1213 +/- 229 milliunits/10(12) RBC in the alcoholics as compared with a value of 997 +/- 120 milliunits/10(12) RBC in the controls (p less than 0.001). The lipase increase was associated with increased values of the mean cellular volume of RBC. A subgroup (64%) of 32 alcoholic subjects with macrocytosis (mean cellular volume greater than 96 femtoliters) showed the highest mean lipase activity (1276 +/- 224 milliunits/10(12) RBC) as compared with a value of 1101 +/- 196 milliunits/10(12) RBC in the normocytic alcoholic subgroup (p less than 0.05). This latter subgroup had a mean value higher (p less than 0.05) than that in the control group. The relationship between values of mean cellular volume and lipase activity was not of predictive value in individual cases. The enzymatic increase was not related to a direct effect of alcohol on the intact RBC. It is postulated that this alteration might result from changes in the chemical and/or physical state of the plasma membrane induced by ethanol during RBC formation. In any event, the increased lipolytic activity of RBC represents a new biological characteristic of alcoholic subjects. Its determination might represent a noninvasive way of evaluating the influence of alcohol on a tissue parameter.